I’ve seen variants of this deck with the 4 mana 7/7 but this deck was much more successful after cutting that card and adding drakes. You want to get out the 4 mana 7/7 turn 4 but that blocks the Finja play on 5 which is a stronger win condition than the 4 mana 7/7 play. I also removed one of the hammer of twilights as the game is usually decided before you can play both.
You want to always try and get Finja on your opening mulligan and you want him down on turn 5 going 1st or turn 4 going second with coin. Keep that in mind when considering keeping overload cards especially Ferals.